chore: fix cilium conformance report

[mlavacca]

What type of PR is this?

/kind documentation

What this PR does / why we need it:

https://github.com/kubernetes-sigs/gateway-api/pull/3137 added a new conformance report for Cilium. The report and the README were malformed in the following way:

• the link to the report in the README was broken
• the link to the cilium release was broken; Cilium v1.16.0 has not been released at the moment of writing yet, therefore I've set here the rc1 link.
• the version of the report was not set and instead was "main". Since the report was for Cilium version 1.16.0, I changed it to 1.16.0.

Once Cilium 1.16.0 gets released, we need to update this report again with the GH link to the new release.

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

NONE

[mlavacca]

@sayboras, please would you be able to update this README with the v1.16.0 release link once it gets released?

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mlavacca, sayboras

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[conformance/OWNERS](https://github.com/kubernetes-sigs/gateway-api/blob/main/conformance/OWNERS)~~ [mlavacca] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[sayboras]

please would you be able to update this README with the v1.16.0 release link once it gets released?

Noted and thanks for the ping.

[robscott]

Thanks @mlavacca!

/lgtm